en:users:documentation:dynamic-power-save
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| + | ===== Dynamic power save ===== | ||
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| + | mac80211 has a feature called //Dynamic power save// which allows the wireless device to dynamically go into power save mode if the device is associated and no network traffic is going through the card for a certain period of time, with a default value set to 100 ms. To enable dynamic power save the wireless driver must support power save mode of operation. | ||
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| + | Some device drivers only power save manually. Some others have it enabled all the time. To enable/disable power save manually you would use: | ||
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| + | <code>iw wlan0 set power_save on</code> | ||
| + | The dynamic power save timeout (the time for no traffic through the card before going to powersave) is affected by the [[en/developers/Documentation/pm-qos|pm-qos]] network latency setting. | ||
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| + | To enable power save a wireless device can sleep at most the duration of the BSS [[en/developers/Documentation/ieee80211/power-savings|DTIM interval]]. It will wake up during that period to listen for beacons from the AP to see if the AP has buffered frames for it. Refer to the [[en/developers/Documentation/ieee80211/power-savings|power savings guide]] for more details as to how this works. | ||
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| + | ===== Drivers with power save enabled by default ===== | ||
| + | * Atheros ath9k for single-chips (>= AR9280) | ||
| + | * TI wl1251 | ||
| + | * TI wl1271 | ||
| + | ===== Ways to tune dynamic power save from userspace ===== | ||
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| + | ==== Default timeout ==== | ||
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| + | You can tune dynamic power save by tuning the default timeout. | ||
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| + | <code>iwconfig wlan0 power 500m</code> | ||
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| + | ==== Network latency ==== | ||
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| + | You can also user [[en/developers/Documentation/pm-qos|pm-qos]] to tune dynamic power save based on network latency requirements of your userspace applications. | ||
en/users/documentation/dynamic-power-save.txt ยท Last modified: 2015/01/26 09:49 (external edit)
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